namespace SALES {
  const int QUARTERS = 4;
  struct Sales {
    double sales[QUARTERS];
    double average;
    double max;
    double min;
  };
  // copies the lesser of 4 or n items from the array ar
  // to the sales member of s and computes and stores the
  // average, maximum, and minimum values of the entered items;
  // remaining elements of sales, if any, set to 0
  void setSales(Sales & s, const double ar[], int n);
  // gathers sales for 4 quarters interactively, stores them
  // in the sales member of s and computes and stores the
  // average, maximum, and minimum values
  void setSales(Sales & s);
  // display all information in structure s
  void showSales(const Sales & s);
}
